Curable resin composition, varnish, and cured product of same

Abstract

The present invention provides: a curable resin composition which has an excellent low dielectric loss tangent; and a cured product of the same. This curable resin composition contains a maleimide resin mixture which is composed of a maleimide resin having repeating units represented by formulae (a) and (b), and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c), and a radical photopolymerization initiator. In the total amount of the maleimide resin mixture, the content of the maleimide resin represented by formula (c) is 5.0 - 30.0 area% in terms of GPC area percentage. (In formula (a), m represents the average number of repetitions, and 0 < m < 200 is satisfied. In formula (b), n represents the average number of repetitions, and 0 < n < 100 is satisfied. (a) and (b) are each bonded at *, and repetition positions may be random.)

Description

Curable resin composition, varnish and cured product thereof

[0001] The present invention relates to a curable resin composition, a varnish, and a cured product thereof, which are suitable for use in semiconductor encapsulants, printed wiring boards, build-up laminates, resist films, electric and electronic components such as optoelectronic boards and optical boards, lightweight, high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics, and 3D printing applications.

[0002] In recent years, the required characteristics of laminates for mounting electrical and electronic components have become more widespread and sophisticated due to the expansion of their application fields. Conventional semiconductor chips were mainly mounted on metal lead frames, but semiconductor chips with high processing power, such as central processing units (hereinafter referred to as CPUs), are increasingly being mounted on laminates made of polymer materials.

[0003] The fifth generation communication system "5G," currently being developed at an accelerated pace, is expected to further increase capacity and speed of communication. 5G will use higher frequencies, but reducing transmission loss is important to achieve high-speed communication using high frequencies, and board materials will be required to have even lower dielectric properties. Transmission loss that occurs on printed circuit boards is due to conductor loss and dielectric loss. As stated in Non-Patent Document 1, dielectric loss α Ｄ is the relative permittivity of the dielectric, ε ｒ and the dielectric loss tangent tanδ, the relative dielectric constant ε ｒ It can be said that improving the dielectric loss tangent tanδ, which has a large contribution to the above, is effective. Thermoplastic materials such as PTFE (polytetrafluoroethylene) and LCP (liquid crystal polymer) are examples of materials with low dielectric loss tangent, but they are less moldable than thermosetting resins. In light of this, there is a need for the development of thermosetting resins with excellent low dielectric properties.

[0004] Furthermore, in order to meet the demand for smaller, thinner, and higher-density semiconductor packages (hereinafter referred to as PKGs) used in smartphones and the like, thinner PKG substrates are being sought, but as the PKG substrate becomes thinner, its rigidity decreases, and problems such as large warpage occur when the PKG is heated during solder mounting on a motherboard (PCB). To alleviate this, there is a demand for PKG substrate materials with a high Tg (260°C) that is equal to or higher than the solder mounting temperature.

[0005] In light of this situation, maleimide resins have been studied in recent years as a material for printed wiring boards in the high-frequency region. Maleimide resins themselves are characterized by high heat resistance due to their high crosslink density, but as pointed out in Patent Document 1 below, bismaleimide compounds having an imide structure in the molecule are highly crystalline and have a high melting point of about 150°C, close to the 170-180°C benchmark for the initiation of self-reaction. Therefore, they are difficult materials to prepare an impregnation varnish, impregnate with it, and dry, or to melt-mix with epoxy resins, curing agents, fillers, etc. to produce molding materials.

[0006] "Signal Loss Factors in High-Speed ​​Signal Transmission on Printed Circuit Boards," 29th Spring Conference of the Japan Institute of Electronics Packaging, Session ID: 16P1-17, 2015

[0007] Japanese Patent Application Publication No. 2018-12671

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a curable resin composition having an excellent low dielectric loss tangent and a cured product thereof.

[0009] That is, the present invention relates to the following [1] to

[10] . In this application, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limits are included. [1] A curable resin composition containing a maleimide resin mixture consisting of a maleimide resin having repeating units of the following formulas (a) and (b) and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c), wherein the content of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the formula (c) is 5.0 to 30.0 area % in terms of GPC area percentage, relative to the total amount of the maleimide resin mixture.

[0010]

[0011] In the above formula (1), m is the average number of repeats, and is 0<m<200. In the above formula (b), n is the average number of repeats, and is 0<n<100. (a) and (b) are each connected with *, and the repeat positions may be random.

[0012]

[0013] [2] The curable resin composition according to the preceding item [1], wherein the maleimide resin mixture is obtained by reacting a styrene-maleic anhydride copolymer, 4,4'-methylenebis(2-ethyl-6-methylaniline), and maleic anhydride. [3] The curable resin composition according to the preceding item [2], wherein the styrene-maleic anhydride copolymer has a weight-average molecular weight of 900 or more but less than 10,000. [4] The curable resin composition according to any one of the preceding items [1] to [3], further comprising at least one selected from the group consisting of a maleimide resin other than the maleimide resin mixture, a polyphenylene ether compound, a compound having an ethylenically unsaturated bond, a cyanate ester resin, polybutadiene and modified products thereof, polystyrene and modified products thereof, and polyethylene and modified products thereof. [5] The curable resin composition according to any one of the preceding items [1] to [4], further comprising a curing accelerator. [6] The curable resin composition according to any one of the preceding items [1] to [5], further comprising a photoradical polymerization initiator. [7] The curable resin composition according to the preceding item [6], which is for use in a resist. [8] The curable resin composition according to any one of the preceding items [1] to [6], which is for use in a printed wiring board. [9] A varnish comprising the curable resin composition according to any one of the preceding items [1] to [8] and an organic solvent.

[10] A cured product obtained by curing the curable resin composition according to any one of the preceding items [1] to [8].

[0014] According to the present invention, it is possible to provide a curable resin composition having an excellent low dielectric loss tangent.

[0015] 1 shows a GPC chart of Synthesis Example 1. 2 shows a GPC chart of Synthesis Example 2. 3 shows a GPC chart of Comparative Synthesis Example 1. 4 shows a GPC chart of Comparative Synthesis Example 2.

[0016] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described in further detail.

[0017] The curable resin composition of this embodiment contains a maleimide resin mixture consisting of a maleimide resin having repeating units of the following formulas (a) and (b) and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c): The maleimide resin contains asymmetric alkyl substituents at the 2- and 6-positions of the aromatic ring contained in the following formulas (b) and (c), which not only makes it possible to control changes in dielectric properties due to water absorption but also disrupts crystallinity, thereby improving solvent solubility and solvent storage stability.

[0018]

[0019] In the above formula, (a) and (b) are each bonded with an asterisk (*), and the repeating positions may be random. m is the average number of repeats, and is preferably 0 < m < 200, more preferably 1 < m < 100, and particularly preferably 5 < m < 80. n is preferably the average number of repeats, and is more preferably 0 < n < 100, even more preferably 0 < n < 90, still more preferably 0 < n < 80, and particularly preferably 1.0 < n < 30. The values ​​of m and n are derived from the styrene-maleic anhydride copolymer used as a raw material, and can be determined from the molecular weight and the ratio of styrene to acid anhydride determined from the acid value in the styrene-maleic anhydride copolymer.

[0020]

[0021] In the total amount of the maleimide resin mixture of this embodiment, the content of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (hereinafter also referred to as "component (c)") represented by the formula (c) is preferably 5.0 to 30.0 area %, and more preferably 10.0 to 20.0 area %, in terms of GPC (gel permeation chromatography) area percentage. If it is more than 30.0%, the proportion of maleimide groups, which are polar groups, increases, resulting in a deterioration in dielectric properties, and component (c) precipitates as crystals, thereby reducing storage stability in the varnish state. If it is less than 5.0%, the proportion of maleimide groups that can be crosslinked decreases, resulting in a deterioration in curability and heat resistance.

[0022] Here, the GPC area percentage of component (c) indicates the ratio of the GPC peak area of ​​component (c) to the sum of the GPC peak areas of the maleimide resin having repeating units of formulas (a) and (b) and the GPC peak area of ​​component (c). That is, the GPC area percentage of component (c) is expressed by the following formula: GPC area percentage of component (c) = (GPC peak area of ​​component (c)) / {(GPC peak area of ​​the maleimide resin having repeating units of formulas (a) and (b)) + (GPC peak area of ​​component (c))} × 100 (%)

[0023] An organic solvent can also be added to the maleimide resin mixture of this embodiment to form a varnish. Examples of organic solvents that can be used include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. The content of the maleimide resin mixture of this embodiment in the varnish is preferably 30 to 90 wt %, more preferably 40 to 80 wt %.

[0024] The maleimide resin mixture of this embodiment may be produced by reacting a styrene-maleic anhydride copolymer with 4,4'-methylenebis(2-ethyl-6-methylaniline) and maleic anhydride. Bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c) is produced by reacting 4,4'-methylenebis(2-ethyl-6-methylaniline) with maleic anhydride. Specifically, the mixture can be produced by a first step in which a styrene-maleic anhydride copolymer and 4,4'-methylenebis(2-ethyl-6-methylaniline) are imidized in a solvent in the presence of a catalyst, followed by a second step in which additional maleic anhydride is added to maleimidize the unreacted 4,4'-methylenebis(2-ethyl-6-methylaniline) to produce bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c). The order of the first and second steps is not limited. For example, after performing the second step of imidizing maleic anhydride and 4,4'-methylenebis(2-ethyl-6-methylaniline) in a solvent in the presence of a catalyst, a styrene-maleic anhydride copolymer may be added to maleimidize the unreacted 4,4'-methylenebis(2-ethyl-6-methylaniline) and the styrene-maleic anhydride copolymer. Alternatively, the styrene-maleic anhydride copolymer and maleic anhydride may be simultaneously reacted with 4,4'-methylenebis(2-ethyl-6-methylaniline). Alternatively, after imidizing the styrene-maleic anhydride copolymer and 4,4'-methylenebis(2-ethyl-6-methylaniline) in a solvent in the presence of a catalyst to obtain a maleimide resin mixture, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by formula (c) may be added and mixed.

[0025] In the imidization step (1), gelation due to three-dimensional crosslinking during the reaction can be prevented by adding an excess of amino groups from 4,4'-methylenebis(2-ethyl-6-methylaniline) per mole of acid anhydride contained in the styrene-maleic anhydride copolymer. In this case, the preferred range for the value (α / β) obtained by dividing the number of moles of amino groups in 4,4'-methylenebis(2-ethyl-6-methylaniline) (α) by the number of moles of acid anhydride in the styrene-maleic anhydride copolymer (β) is 1.1 to 20, preferably 1.1 to 15, and more preferably 1.1 to 10. If α / β is less than the above range, gelation occurs, making production difficult. Furthermore, if α / β exceeds the above range, the amount of polystyrene incorporated decreases, preventing sufficient improvement in electrical properties. Examples of solvents that can be used include, but are not limited to, water-insoluble solvents such as aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, and ketone solvents such as methyl isobutyl ketone and cyclopentanone. Two or more of these solvents may be used in combination. Furthermore, aprotic polar solvents may also be used in combination with the water-insoluble solvents. Examples include dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, and N-methylpyrrolidone. Two or more of these solvents may also be used in combination. When using an aprotic polar solvent, it is preferable to use one with a higher boiling point than the water-insoluble solvent to be used in combination. During the reaction, as needed, a catalyst may be used, such as hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, p-toluenesulfonic acid, or methanesulfonic acid; Lewis acids such as aluminum chloride or zinc chloride; solid acids such as activated clay, acid clay, white carbon, zeolite, or silica alumina; or acidic ion exchange resins. These may be used alone or in combination of two or more. The amount of catalyst used is usually 0.1 to 0.8 mol, and preferably 0.2 to 0.7 mol, per mol of amino groups in the amine compound used. If the amount of catalyst used is too large, the viscosity of the reaction solution may become too high, making stirring difficult; if the amount is too small, the reaction may proceed slowly.In the second imidization step, maleic anhydride is added in an amount at least equivalent, preferably at least 1.1 equivalents, relative to the molar number of amino groups in the excess 4,4'-methylenebis(2-ethyl-6-methylaniline) charged in the first step, thereby enabling all of the remaining 4,4'-methylenebis(2-ethyl-6-methylaniline) to be maleimidized. Furthermore, a basic cocatalyst such as triethylamine can be used alone or in combination as a cocatalyst for imidization. When a sulfonic acid or other catalyst is used, neutralization with an alkali metal such as sodium hydroxide or potassium hydroxide may be performed before proceeding to the extraction step. For the extraction step, an aromatic hydrocarbon solvent such as toluene or xylene may be used alone, or a non-aromatic hydrocarbon such as cyclohexane or toluene may be used in combination. After extraction, the organic layer is washed with water until the wastewater becomes neutral, and the solvent is removed using an evaporator or the like to obtain the desired maleimide resin having a polystyrene structure within the molecule.

[0026] Styrene-maleic anhydride copolymers can be obtained by copolymerizing styrene and maleic anhydride. The polymerization method can be any known method, including radical polymerization, coordination polymerization, and various living polymerizations. For example, the copolymer can be obtained by reacting styrene and maleic anhydride in toluene in the presence of a radical polymerization initiator. The resulting polymer may be a random polymer or a periodic copolymer, or may be a block polymer or an alternating copolymer. The stereoregularity of the polystyrene segments may be syndiotactic, atactic, isotactic, or the like.

[0027] The weight average molecular weight (Mw) of the styrene-maleic anhydride copolymer, as determined by gel permeation chromatography (GPC), is preferably 900 or more and less than 10,000, more preferably 1,500 or more and less than 9,000, and particularly preferably 2,000 or more and less than 8,000. The number average molecular weight (Mn) is preferably 1,000 or more and less than 5,000, and more preferably 1,000 or more and less than 3,000. When the weight average molecular weight (Mw) and number average molecular weight (Mn) are less than the upper limit values, gelation can be prevented, and purification by water washing becomes easy. When the weight average molecular weight (Mw) and number average molecular weight (Mn) are equal to or greater than the lower limit values, the target compound does not volatilize during the solvent distillation step.

[0028] The weight average molecular weight (Mw) of the maleimide resin mixture of this embodiment, as determined by gel permeation chromatography (GPC), is preferably 1,000 or more but less than 100,000, more preferably 1,000 or more but less than 7,000, and particularly preferably 2,000 or more but less than 6,000. The number average molecular weight (Mn) is preferably 1,000 or more but less than 5,000, and more preferably 1,000 or more but less than 2,000. It is preferable for the weight average molecular weight (Mw) and number average molecular weight (Mn) to be less than the upper limit values, as this results in excellent solvent solubility. It is also preferable for the weight average molecular weight (Mw) and number average molecular weight (Mn) to be equal to or greater than the lower limit values, as this results in less volatile content during molding, making molding defects less likely to occur.

[0029] The maleimide equivalent of the maleimide resin mixture of this embodiment can be determined by potentiometric titration. The maleimide equivalent of the maleimide resin mixture of this embodiment is preferably 500 g / eq or more but less than 3000 g / eq, more preferably 500 g / eq or more but less than 2000 g / eq, and particularly preferably 600 g / eq or more but less than 1500 g / eq. A maleimide equivalent less than the upper limit described above is preferred because it contains maleimide groups, which are crosslinking components, and is incorporated into the cured network, thereby reducing molding defects and increasing the glass transition temperature (Tg). Furthermore, a maleimide equivalent equal to or greater than the lower limit described above is preferred because it contains fewer highly polar maleimide groups in the cured product, allowing for control of changes in properties due to water absorption.

[0030] The curable composition of this embodiment may contain a polymerization inhibitor in addition to the maleimide resin mixture of this embodiment. The inclusion of a polymerization inhibitor improves storage stability and allows for control of the reaction initiation temperature. Controlling the reaction initiation temperature facilitates ensuring fluidity, preventing impregnation into glass cloth and facilitating B-staging, such as prepreg formation. If the polymerization reaction proceeds too quickly during prepreg formation, problems such as difficulty in lamination during the lamination process are likely to occur. Usable polymerization inhibitors include phenol-based, sulfur-based, phosphorus-based, hindered amine-based, nitroso-based, and nitroxyl radical-based inhibitors. The polymerization inhibitor may be added during or after synthesis of the maleimide resin mixture of this embodiment. The polymerization inhibitors may be used alone or in combination of two or more. The amount of polymerization inhibitor used is typically 0.008 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of the resin component. These polymerization inhibitors may be used alone, or two or more may be used in combination. In this embodiment, phenol-based, hindered amine-based, nitroso-based, and nitroxyl radical-based compounds are preferred.

[0031] Specific examples of phenolic polymerization inhibitors include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-p-ethylphenol, stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3, Monophenols such as 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), Triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] ) propionate], 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 3,9-bis[1,1-dimethyl-2-{β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane, bis(3,5-di-t-butyl-4-hydroxybenzylsulfonate)calcium and other bisphenols;Examples include polymeric phenols such as 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0032] Specific examples of sulfur-based polymerization inhibitors include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, and distearyl-3,3'-thiodipropionate.

[0033] Specific examples of phosphorus-based polymerization inhibitors include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol phosphite, tris(2,4-di-t-butylphenyl) phosphite, cyclic neopentane tetrayl bis(octadecyl) phosphite, cyclic neopentane tetrayl bis(2,4-di-t-butylphenyl) phosphite, and cyclic neopentane tetrayl bis(2,4-di-t-butyl-4-methylphenyl) phosphite. and phosphites such as bis[2-t-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogenphosphite; and oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0034] Specific examples of hindered amine polymerization inhibitors include ADK STAB (registered trademark) LA-40MP, ADK STAB LA-40Si, ADK STAB LA-402AF, ADK STAB LA-87, DEKA STAB LA-82, DEKA STAB LA-81, ADK STAB LA-77Y, ADK STAB LA-77G, ADK STAB LA-72, ADK STAB LA-68, ADK STAB LA-63P, ADK STAB LA-57, and ADK STAB LA-52 (all manufactured by AD Corporation). Examples of such a solvent include, but are not limited to, Tinuvin (registered trademark), ...

[0035] Specific examples of the nitroso-based polymerization inhibitor include p-nitrosophenol, N-nitrosodiphenylamine, and the ammonium salt of N-nitrosophenylhydroxyamine (cupferron), with the ammonium salt of N-nitrosophenylhydroxyamine (cupferron) being preferred.

[0036] Specific examples of nitroxyl radical polymerization inhibitors include di-tert-butyl nitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and the like, but are not limited to these.

[0037] The curable resin composition of this embodiment can use any known material as the curable resin other than the maleimide resin of this embodiment and component (c). Specific examples include the maleimide resin of this embodiment and maleimide resins other than component (c), phenolic resins, epoxy resins, amine resins, compounds containing ethylenically unsaturated bonds, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, propenyl resins, methallyl resins, and active ester resins. These may be used alone or in combination. Furthermore, in terms of the balance of heat resistance, adhesion, and dielectric properties, it is preferable to include an epoxy resin, a compound containing an ethylenically unsaturated bond, or a cyanate ester resin. The inclusion of these curable resins can improve the brittleness of the cured product and its adhesion to metals, thereby suppressing package cracking during solder reflow and reliability tests such as thermal cycling. The amount of the curable resin used is preferably 10 times or less by weight, more preferably 5 times or less, and particularly preferably 3 times or less by weight relative to the maleimide resin mixture of this embodiment. The lower limit is preferably 0.5 times by weight or more, and more preferably 1 time by weight or more. If the amount is 10 times by weight or less, the effects of the heat resistance and dielectric properties of the maleimide resin mixture of this embodiment can be utilized.

[0038] Examples of the maleimide resin of this embodiment and maleimide resins other than component (c), phenolic resins, epoxy resins, amine resins, compounds containing an ethylenically unsaturated bond, isocyanate resins, polyamide resins, polyimide resins, cyanate ester resins, and active ester resins that can be used include those exemplified below.

[0039] Maleimide resins of the present embodiment and maleimide resins other than component (c): 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy)phenyl]propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), Xylox-type maleimide compounds (anilix maleimide, manufactured by Mitsui Chemicals Fine Co., Ltd.), biphenylaralkyl-type maleimide compounds (solidified by distilling off the solvent under reduced pressure from a resin solution containing the maleimide compound (M2) described in Example 4 of JP 2009-001783 A), bisaminocumylbenzene-type maleimide (maleimide compounds described in WO 2020 / 054601 A), maleimide compounds having an indane structure described in Japanese Patent No. 6629692 or WO 2020 / 217679, MATERIAL STAGE Vol. 18, No. 12 2019 "Continued Epoxy Resin CAS Number Story - Curing Agent CAS Number Memorandum No. 31 Bismaleimide (1)" and MATERIAL STAGE Vol. 19, No. 12 2019 2 2019 Maleimide compound described in "Continued Epoxy Resin CAS Number Story - Hardener CAS Number Memorandum No. 32 Bismaleimide (2)".

[0040] Phenolic resins: Polycondensates of phenols (phenol, alkyl-substituted phenols, aromatic-substituted phenols, hydroquinone, resorcinol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, furfural, etc.), polycondensates of phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydrofuran, etc.), phenolic resins obtained by polycondensation of phenols and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.) or substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene, etc.); polycondensates of bisphenols and various aldehydes; and polyphenylene ether compounds.

[0041] Any known polyphenylene ether compound may be used, but from the viewpoint of heat resistance and electrical properties, a polyphenylene ether compound having an ethylenically unsaturated double bond is preferred, and a polyphenylene ether compound having an acrylic group, a methacrylic group, or a styrene structure is more preferred. Commercially available products include SA-9000-111 (manufactured by SABIC Corporation, a polyphenylene ether compound having a methacrylic group), OPE-2St 1200, and OPE-2St 2200 (manufactured by Mitsubishi Gas Chemical Company, a polyphenylene ether compound having a styrene structure). The number average molecular weight (Mn) of the polyphenylene ether compound is preferably 500 to 5,000, more preferably 2,000 to 5,000, and even more preferably 2,000 to 4,000. If the molecular weight is less than 500, the heat resistance of the cured product tends to be insufficient. Furthermore, if the molecular weight is greater than 5,000, the melt viscosity increases, and sufficient fluidity cannot be obtained, which tends to result in molding defects. Furthermore, the reactivity decreases, the curing reaction takes a long time, and the amount of unreacted polyphenylene ether not incorporated into the curing system increases, which lowers the glass transition temperature of the cured product and reduces the heat resistance of the cured product. If the number average molecular weight of the polyphenylene ether compound is 500 to 5,000, it is possible to exhibit excellent heat resistance and moldability while maintaining excellent dielectric properties. The number average molecular weight here can be measured specifically using gel permeation chromatography or the like.

[0042] The polyphenylene ether compound may be one obtained by a polymerization reaction or one obtained by a redistribution reaction of a high-molecular-weight polyphenylene ether compound having a number-average molecular weight of approximately 10,000 to 30,000. Furthermore, these compounds may be used as raw materials and reacted with a compound having an ethylenically unsaturated double bond, such as methacryl chloride, acrylic chloride, or chloromethylstyrene, to impart radical polymerizability. A polyphenylene ether compound obtained by a redistribution reaction may be obtained, for example, by heating a high-molecular-weight polyphenylene ether compound in a solvent such as toluene in the presence of a phenolic compound and a radical initiator to cause a redistribution reaction. Such polyphenylene ether compounds obtained by a redistribution reaction are preferred because they have hydroxyl groups derived from the phenolic compound at both ends of the molecular chain that contribute to curing, thereby maintaining even higher heat resistance. Furthermore, functional groups can be introduced at both ends of the molecular chain even after modification with a compound having an ethylenically unsaturated double bond. Furthermore, polyphenylene ether compounds obtained by a polymerization reaction are preferred because they exhibit excellent fluidity.

[0043] In the case of polyphenylene ether compounds obtained by polymerization, the molecular weight of the polyphenylene ether compound can be adjusted by adjusting the polymerization conditions, etc. In the case of polyphenylene ether compounds obtained by redistribution, the molecular weight of the resulting polyphenylene ether compound can be adjusted by adjusting the conditions, etc. of the redistribution reaction. More specifically, adjusting the amount of the phenolic compound used in the redistribution reaction can be considered. That is, the greater the amount of the phenolic compound, the lower the molecular weight of the resulting polyphenylene ether compound. In this case, poly(2,6-dimethyl-1,4-phenylene ether) or the like can be used as the high-molecular-weight polyphenylene ether compound that undergoes the redistribution reaction. Furthermore, the phenolic compound used in the redistribution reaction is not particularly limited, but preferred are, for example, polyfunctional phenolic compounds having two or more phenolic hydroxyl groups per molecule, such as bisphenol A, phenol novolac, and cresol novolac. These compounds may be used alone or in combination of two or more.

[0044] The content of the polyphenylene ether compound is not particularly limited, but is preferably 10 to 90 wt %, and more preferably 20 to 80 wt %, relative to the total weight of the curable resin components. A polyphenylene ether compound content of 10 to 90 wt % is preferable in that it not only provides excellent heat resistance, etc., but also allows a cured product to fully exhibit the excellent dielectric properties of the polyphenylene ether compound.

[0045] Epoxy resins: glycidyl ether-based epoxy resins obtained by glycidylating the above-mentioned phenolic resins and alcohols, alicyclic epoxy resins typified by 4-vinyl-1-cyclohexene diepoxide and 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate, glycidylamine-based epoxy resins typified by tetraglycidyldiaminodiphenylmethane (TGDDM) and triglycidyl-p-aminophenol, and glycidyl ester-based epoxy resins.

[0046] Amine resins: diaminodiphenylmethane, diaminodiphenyl sulfone, isophoronediamine, naphthalenediamine, aniline novolak, orthoethylaniline novolak, aniline resins obtained by reacting aniline with xylylene chloride, and aniline and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-biphenyl, 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.) or substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, 1,4-bis(hydroxymethyl)benzene, etc.) described in Japanese Patent No. 6,429,862.

[0047] Compounds containing an ethylenically unsaturated bond: polycondensates of the above-mentioned phenol resins and ethylenically unsaturated bond-containing halogen-based compounds (chloromethylstyrene, allyl chloride, methallyl chloride, acrylic acid chloride, allyl chloride, etc.), polycondensates of ethylenically unsaturated bond-containing phenols (2-allylphenol, 2-propenylphenol, 4-allylphenol, 4-propenylphenol, eugenol, isoeugenol, etc.) and halogen-based compounds (4,4'-bis(methoxymethyl)-1,1'-biphenyl, 1,4-bis(chloromethyl)benzene, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-dibromobenzophenone, cyanuric chloride, etc.), polycondensates of epoxy resins or alcohols and substituted or unsubstituted acrylates (acrylate, methacrylate, etc.), styrene resins, allyl Group-containing compounds, acenaphthyl group-containing compounds (acenaphthylene, etc.), isocyanuric acid derivatives (TAIC manufactured by Mitsubishi Chemical Corporation, MA-DGIC, DA-MGIC, MeDAIC, L-DAIC, DD-1 manufactured by Shikoku Chemicals, etc.), maleimide compounds (phenylmaleimide, 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, m-phenylene bismaleimide, 2,2'-bis[4-(4-maleimidophenoxy) (si) phenyl)propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene), Zylok type maleimide resin (Anilix Maleimide, manufactured by Mitsui Fine Chemicals Co., Ltd.), biphenylaralkyl type maleimide resin (a resin solution containing the maleimide resin (M2) described in Example 4 of JP 2009-001783 A, solidified by distilling off the solvent under reduced pressure), bisaminocumylbenzene type maleimide (maleimide resin described in WO 2020 / 054601 A).

[0048] Isocyanate resins: aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate; polyisocyanates such as biuret compounds of one or more types of isocyanate monomers or isocyanate compounds obtained by trimerizing the above diisocyanate compounds; and polyisocyanates obtained by a urethanization reaction of the above isocyanate compounds with polyol compounds.

[0049] Polyamide resin: a polymer made primarily from one or more amino acids (e.g., 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, para-aminomethylbenzoic acid, etc.) and lactams (e.g., ε-caprolactam, ω-undecanelactam, ω-laurolactam); or a polymer made primarily from one or more diamines and one or more dicarboxylic acids. Diamines: aliphatic diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,5-diaminopentane, and 2-methyl-1,8-diaminooctane; alicyclic diamines such as cyclohexanediamine, bis-(4-aminocyclohexyl)methane, and bis(3-methyl-4-aminocyclohexyl)methane; and aromatic diamines such as xylylenediamine. Dicarboxylic acids: aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and dialkyl esters and dichlorides of these dicarboxylic acids.

[0050] Polyimide resin: a polycondensate of the above diamine and a tetracarboxylic dianhydride. Tetracarboxylic dianhydride: 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2dicarboxylic anhydride, pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonyltetracarboxylic dianhydride, sulfone tetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride, 2,2'-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, O-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy) phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-Naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane -1,2,3,4-tetracarboxylic acid dianhydride, cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic acid dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4'-bis(cyclohexane- 1,2-dicarboxylic acid) dianhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel-[1S,5R,6R] -3-oxabicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) ether, 4,4'-biphenylbis(trimellitic acid monoester acid anhydride), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

[0051] Cyanate ester resin: a cyanate ester compound obtained by reacting a phenolic resin with a cyanogen halide. Specific examples include dicyanatobenzene, tricyanatobenzene, dicyanatonaphthalene, dicyanatobiphenyl, 2,2-bis(4-cyanatophenyl)propane (BisA-OCN, manufactured by Mitsubishi Gas Chemical Company, Inc.), bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(3,5-dimethyl-4-cyanatophenyl)propane, 2,2-bis(4-cyanatophenyl)ethane, 2,2-bis(4-cyanatophenyl)hexafluoropropane, bis(4-cyanatophenyl)sulfone, bis(4-cyanatophenyl)thioether, phenol novolac cyanate, and phenol-dicyclopentadiene co-condensates in which the hydroxyl groups have been converted to cyanate groups, but are not limited to these. Furthermore, the cyanate ester compound, the synthesis method of which is described in Japanese Patent Application Laid-Open No. 2005-264154, is particularly preferred as a cyanate ester compound due to its low moisture absorption, flame retardancy, and excellent dielectric properties. If necessary, the cyanate ester resin may contain a catalyst such as zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octoate, tin octoate, lead acetylacetonate, dibutyltin maleate, or commercially available 18% Octope (registered trademark) Zn (manufactured by Hope Pharmaceutical Co., Ltd.) to trimerize the cyanate group to form a sym-triazine ring. The catalyst is typically used in an amount of 0.0001 to 0.10 parts by weight, preferably 0.00015 to 0.0015 parts by weight, per 100 parts by weight of the total weight of the curable resin composition.

[0052] Active ester resin: A compound having one or more active ester groups per molecule can be used as a curing agent for curable resins other than the maleimide resin mixture of this embodiment, such as epoxy resins, if necessary. Preferred active ester resins are compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. The active ester resin is preferably one obtained by a condensation reaction between at least one of a carboxylic acid compound and a thiocarboxylic acid compound and at least one of a hydroxy compound and a thiol compound. In particular, from the viewpoint of improving heat resistance, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and at least one of a phenol compound and a naphthol compound are preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalene, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene-type diphenol compounds, phenol novolak, etc. Here, "dicyclopentadiene-type diphenol compounds" refers to diphenol compounds obtained by condensing one dicyclopentadiene molecule with two phenol molecules.Preferred specific examples of the active ester resin include active ester resins containing a dicyclopentadiene-type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated product of phenol novolac, and active ester resins containing a benzoylated product of phenol novolac. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene-type diphenol structure are more preferred. The "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene. Commercially available active ester resins include, for example, active ester resins containing a dicyclopentadiene-type diphenol structure such as "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", "EXB-8000L-65TM", and "EXB-8150-65T" (manufactured by DIC Corporation); active ester resins containing a bisphenol A-type structure such as "Unifiner (registered trademark) series" (manufactured by Unitika Ltd.); and active ester resins containing a naphthalene structure such as Examples of active ester resins containing acetylated phenol novolac include "EXB9416-70BK" (manufactured by DIC Corporation); "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing benzoylated phenol novolac include "YLH1026", "YLH1030", and "YLH1048" (manufactured by Mitsubishi Chemical Corporation); "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin which is an acetylated phenol novolac; and "EXB-9050L-62M" (manufactured by DIC Corporation) as an active ester resin containing a phosphorus atom.

[0053] The curable resin composition of the present embodiment can also be used in combination with a curing accelerator (curing catalyst) to improve the curability. Specific examples of curing accelerators that can be used include radical polymerization initiators, which are preferably used for the purpose of promoting self-polymerization of radically polymerizable curable resins such as olefin compounds and maleimide resins, or radical polymerization with other components. Examples of the radical polymerization initiator that can be used include ketone peroxides such as methyl ethyl ketone peroxide and acetylacetone peroxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide and 1,3-bis-(t-butylperoxyisopropyl)-benzene, peroxyketals such as t-butyl peroxybenzoate and 1,1-di-t-butylperoxycyclohexane, α-cumylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, and t-amylperoxy-3,5,5-trimethylhexanoate. peroxycarbonates such as di-2-ethylhexyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyoctoate, lauroyl peroxide; and known curing accelerators such as azo compounds such as azobisisobutyronitrile, 4,4'-azobis(4-cyanovaleric acid), and 2,2'-azobis(2,4-dimethylvaleronitrile), but are not particularly limited thereto. Ketone peroxides, diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, alkyl peresters, percarbonates, etc. are preferred, and dialkyl peroxides are more preferred.The amount of radical polymerization initiator added is preferably 0.01 to 5 parts by weight, and particularly preferably 0.01 to 3 parts by weight, per 100 parts by weight of the curable resin composition. If the amount of radical polymerization initiator used is too large, the molecular weight does not sufficiently elongate during the polymerization reaction.

[0054] Furthermore, if necessary, a curing accelerator other than the radical polymerization initiator may be added or used in combination. Specific examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, tertiary amines such as 2-(dimethylaminomethyl)phenol and 1,8-diaza-bicyclo(5,4,0)undecene-7, phosphines such as triphenylphosphine, quaternary ammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide, and triphenylammonium salts such as tetrabutylammonium salt, triisopropylmethylammonium salt, trimethyldecanylammonium salt, cetyltrimethylammonium salt, and hexadecyltrimethylammonium hydroxide. Examples of the curing accelerator include quaternary phosphonium salts such as phenylbenzylphosphonium salt, triphenylethylphosphonium salt, and tetrabutylphosphonium salt (the counter ion of the quaternary salt may be a halogen, an organic acid ion, a hydroxide ion, or the like, and is not particularly limited, but organic acid ions and hydroxide ions are particularly preferred), and transition metal compounds (transition metal salts) such as zinc compounds such as tin octoate, zinc carboxylate (zinc 2-ethylhexanoate, zinc stearate, zinc behenate, zinc myristylate), and zinc phosphate esters (zinc octylphosphate, zinc stearylphosphate, etc.). The curing accelerator is used in an amount of 0.01 to 5.0 parts by weight per 100 parts by weight of the epoxy resin, as needed.

[0055] The curable resin composition of this embodiment may contain a phosphorus-containing compound as a flame retardant-imparting component. The phosphorus-containing compound may be a reactive type or an additive type. Specific examples of the phosphorus-containing compound include phosphate esters such as trimethyl phosphate, triethyl phosphate, tricresyl phosphate, trixylylenyl phosphate, cresyl diphenyl phosphate, cresyl-2,6-dixylylenyl phosphate, 1,3-phenylenebis(dixylylenyl phosphate), 1,4-phenylenebis(dixylylenyl phosphate), and 4,4'-biphenyl(dixylylenyl phosphate); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 10(2,5- Examples of suitable compounds include phosphanes such as (dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; phosphorus-containing epoxy compounds obtained by reacting an epoxy resin with the active hydrogen of the phosphanes; and red phosphorus. However, phosphate esters, phosphanes, or phosphorus-containing epoxy compounds are preferred, with 1,3-phenylenebis(dixylylenyl phosphate), 1,4-phenylenebis(dixylylenyl phosphate), 4,4'-biphenyl(dixylylenyl phosphate), or phosphorus-containing epoxy compounds being particularly preferred. The content of the phosphorus-containing compound is preferably in the range of 0.1 to 0.6 (weight ratio) (phosphorus-containing compound) / (total epoxy resin). If the ratio is 0.1 or less, flame retardancy is insufficient, while if it is 0.6 or more, there is a concern that the moisture absorption and dielectric properties of the cured product may be adversely affected.

[0056] Furthermore, a light stabilizer may be added to the curable resin composition of this embodiment as needed. As the light stabilizer, a hindered amine light stabilizer (Hindered Amine Light Stabilizers, HALS) or the like is suitable. HALS is not particularly limited, but typical examples include polycondensates of dibutylamine, 1,3,5-triazine, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, polycondensates of dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl) bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), and the like. Only one type of HALS may be used, or two or more types may be used in combination.

[0057] Furthermore, a binder resin can be blended into the curable resin composition of this embodiment as needed. Examples of binder resins include, but are not limited to, butyral resins, acetal resins, acrylic resins, epoxy-nylon resins, NBR-phenol resins, epoxy-NBR resins, polyamide resins, polyimide resins, and silicone resins. The blending amount of the binder resin is preferably within a range that does not impair the flame retardancy and heat resistance of the cured product, and is preferably 0.05 to 50 parts by weight, more preferably 0.05 to 20 parts by weight, per 100 parts by weight of the resin component, as needed.

[0058] Furthermore, to the curable resin composition of this embodiment, if necessary, inorganic fillers such as powders such as fused silica, crystalline silica, porous silica, alumina, zircon, calcium silicate, calcium carbonate, quartz powder, silicon carbide, silicon nitride, boron nitride, zirconia, aluminum nitride, graphite, forsterite, steatite, spinel, mullite, titania, talc, clay, iron oxide asbestos, and glass powder, or spherical or crushed versions of these, may be added. In particular, when a curable resin composition for semiconductor encapsulation is obtained, the amount of the inorganic filler used is typically 80 to 92 wt %, and preferably 83 to 90 wt %, of the curable resin composition.

[0059] The curable resin composition of this embodiment can contain known additives as needed. Specific examples of usable additives include polybutadiene and modified products thereof, modified acrylonitrile copolymers, polyphenylene ether, polystyrene and modified products thereof, polyethylene and modified products thereof, polyimide, fluororesin, silicone gel, silicone oil, surface treatment agents for fillers such as silane coupling agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green. The amount of these additives added is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and particularly preferably 10 parts by weight or less, per 100 parts by weight of the curable resin composition. From the perspectives of low water absorption and electrical properties, polybutadiene and modified products thereof, polyphenylene ether, polystyrene and modified products thereof, polyethylene and modified products thereof, fluororesin, etc. are preferred. From the perspectives of electrical properties, adhesion, and low water absorption, polystyrene and modified products thereof, polyethylene and modified products thereof, and polybutadiene and modified products thereof are preferred. Specific examples include butadiene-based thermoplastic elastomers such as styrene-butadiene copolymers (SBR: RICON-100, RICON-181, RICON-184, all manufactured by Cray Valley Corporation, etc.) and acrylonitrile-butadiene copolymers; and styrene-based thermoplastic elastomers such as styrene-butadiene-styrene copolymers (SBS), hydrogenated styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers (SIS), hydrogenated styrene-isoprene-styrene copolymers, hydrogenated styrene-(butadiene / isoprene)-styrene copolymers, and styrene-ethylene-propylene-styrene copolymers. These styrene-based thermoplastic elastomers may be used alone or in combination of two or more.Among these high molecular weight materials, styrene-based thermoplastic elastomers such as styrene-butadiene-styrene copolymer, hydrogenated styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, hydrogenated styrene-isoprene-styrene copolymer, and hydrogenated styrene-(butadiene / isoprene)-styrene copolymer are preferred, and in particular, styrene-isoprene-styrene copolymer, hydrogenated styrene-butadiene-styrene copolymer, hydrogenated styrene-isoprene-styrene copolymer, hydrogenated styrene-(butadiene / isoprene)-styrene copolymer, and styrene-ethylene-propylene-styrene copolymer are more preferred because they have higher heat resistance and are less susceptible to oxidative degradation. Specifically, Septon 1020, Septon 2002, Septon 2004F, Septon 2005, Septon 2006, Septon 2063, Septon 2104, Septon 4003, Septon 4044, Septon 4055, Septon 4077, Septon 4099, Septon 8004, Septon 8006, Septon 8007L, Septon HG252, Septon V9827, Hybra 7125 (hydrogenated), Hybra 7215F, Hybra 7311F, Septon The weight-average molecular weight of the styrene-based thermoplastic elastomer is not particularly limited as long as it is 10,000 or greater. However, if it is too large, compatibility with polyphenylene ether compounds, low-molecular-weight components with weight-average molecular weights of approximately 50 to 1,000, and oligomer components with weight-average molecular weights of approximately 1,000 to 5,000 is impaired, making it difficult to ensure blending and solvent stability. Therefore, a weight-average molecular weight of approximately 10,000 to 300,000 is preferred. Generally, compounds containing heteroatoms such as oxygen and nitrogen, such as bismaleimides and polymaleimides, have difficulty ensuring compatibility with low-polarity compounds, such as compounds composed primarily or exclusively of hydrocarbons, among the additives and curable resin components mentioned above, due to their polarity. On the other hand, the maleimide resin mixture of this embodiment does not have a skeleton design that actively incorporates heteroatoms such as oxygen and nitrogen (i.e., it has few polar groups), and therefore exhibits excellent compatibility with materials with low polarity and low dielectric tangents, as well as compounds composed exclusively of hydrocarbons.

[0060] The curable resin composition of this embodiment can be obtained by uniformly mixing the above components in a predetermined ratio, and is typically pre-cured at 130 to 180°C for 30 to 500 seconds, and then post-cured at 150 to 250°C for 2 to 15 hours, thereby allowing the curing reaction to proceed sufficiently and producing a cured product of this embodiment. Alternatively, the components of the curable resin composition can be uniformly dispersed or dissolved in a solvent or the like, and the solvent can be removed before curing.

[0061] The curable resin composition of this embodiment obtained in this manner has moisture resistance, heat resistance, and high adhesion. Therefore, the curable resin composition of this embodiment can be used in a wide range of fields requiring moisture resistance, heat resistance, and high adhesion. Specifically, it is useful as a material for all electrical and electronic components, such as insulating materials, laminates (printed wiring boards, BGA substrates, build-up substrates, etc.), encapsulating materials, and resists. It can also be used in fields such as molding materials, composite materials, paint materials, adhesives, and 3D printing. In particular, solder reflow resistance is beneficial in semiconductor encapsulation.

[0062] The semiconductor device may be encapsulated with the curable resin composition of the present embodiment, and examples of the semiconductor device include a DIP (dual in-line package), a QFP (quad flat package), a BGA (ball grid array), a CSP (chip size package), a SOP (small outline package), a TSOP (thin small outline package), and a TQFP (thin quad flat package).

[0063] The method for preparing the curable resin composition of this embodiment is not particularly limited, and the components may be simply mixed uniformly, or may be prepolymerized. For example, the maleimide resin mixture of this embodiment may be prepolymerized by heating it in the presence or absence of a catalyst and in the presence or absence of a solvent. Similarly, in addition to the maleimide resin mixture of this embodiment, a curing agent such as an epoxy resin, an amine compound, a maleimide-based compound, a cyanate ester compound, a phenolic resin, or an acid anhydride compound, and other additives may be added to form a prepolymer. The components may be mixed or prepolymerized using, for example, an extruder, kneader, or rolls in the absence of a solvent, or a reaction kettle equipped with a stirrer in the presence of a solvent.

[0064] The uniform mixing method involves kneading the components using a device such as a kneader, roll, or planetary mixer at a temperature within the range of 50 to 100°C to obtain a uniform resin composition. The resulting resin composition can be pulverized and then molded into cylindrical tablets using a molding machine such as a tablet machine, or into granular powder or powder-like molded bodies. Alternatively, these compositions can be melted on a surface support and molded into sheets with a thickness of 0.05 mm to 10 mm to obtain molded curable resin compositions. The resulting molded bodies are non-sticky at 0 to 20°C, and exhibit little loss in fluidity or curability even when stored at -25 to 0°C for one week or more. The resulting molded bodies can be molded into cured products using a transfer molding machine or compression molding machine.

[0065] An organic solvent can also be added to the curable resin composition of this embodiment to form a varnish-like composition (hereinafter simply referred to as varnish). The curable resin composition of this embodiment can be dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, or N-methylpyrrolidone, as needed, to form a varnish. This varnish is then impregnated into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper, and heated and dried to obtain a prepreg. This prepreg can then be hot-press molded to form a cured product of the curable resin composition of this embodiment. The solvent used in this process typically accounts for 10 to 70 wt %, preferably 15 to 70 wt %, of the mixture of the curable resin composition of this embodiment and the solvent. Furthermore, if the composition is in liquid form, a cured curable resin containing carbon fiber can also be obtained as is, for example, by the RTM (Resin Transfer Molding) method.

[0066] The curable resin composition of this embodiment can also be used as a modifier for film-type resin compositions. Specifically, it can be used to improve flexibility and the like in the B-stage. Such a film-type resin composition can be obtained as a sheet-like adhesive by applying the curable resin composition of this embodiment as a varnish onto a release film, removing the solvent under heating, and then performing B-staging. This sheet-like adhesive can be used as an interlayer insulating layer in a multilayer substrate or the like.

[0067] The curable resin composition of this embodiment can be heated and melted to reduce viscosity, and then impregnated into reinforcing fibers such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, and alumina fiber to obtain a prepreg. Specific examples include glass fibers such as E-glass cloth, D-glass cloth, S-glass cloth, Q-glass cloth, spherical glass cloth, NE-glass cloth, and T-glass cloth; inorganic fibers other than glass; polyparaphenylene terephthalamide (Kevlar®, manufactured by DuPont Co., Ltd.); wholly aromatic polyamide; polyester; and organic fibers such as polyparaphenylene benzoxazole, polyimide, and carbon fiber, but are not limited thereto. The shape of the substrate is not particularly limited, but examples include woven fabric, nonwoven fabric, roving, and chopped strand mat. Known weaving methods for woven fabrics include plain weave, saddle-weave, and twill weave, and these known methods can be appropriately selected and used depending on the intended application and performance. Also preferred are woven fabrics that have been subjected to fiber-opening treatment and glass woven fabrics that have been surface-treated with a silane coupling agent or the like. The thickness of the substrate is not particularly limited, but is preferably about 0.01 to 0.4 mm. Also, a prepreg can be obtained by impregnating reinforcing fibers with the varnish and drying the impregnated fibers by heating.

[0068] The laminate of this embodiment comprises one or more of the above prepregs. The laminate is not particularly limited as long as it comprises one or more prepregs, and may also comprise any other layer. The method for manufacturing the laminate can be any generally known method, and is not particularly limited. For example, when molding a metal foil-clad laminate, a multi-stage press, a multi-stage vacuum press, a continuous molding machine, an autoclave molding machine, or the like can be used. The prepregs are laminated together and then heated and pressure molded to obtain a laminate. The heating temperature is not particularly limited, but is preferably 65 to 300°C, and more preferably 120 to 270°C. The pressure applied is also not particularly limited, but if the pressure is too high, it becomes difficult to adjust the solid content of the resin in the laminate, resulting in unstable quality. If the pressure is too low, air bubbles will form and adhesion between the laminate layers will be poor. Therefore, a pressure of 2.0 to 5.0 MPa is preferred, and 2.5 to 4.0 MPa is more preferred. The laminate of this embodiment, having a layer made of metal foil, can be suitably used as a metal foil-clad laminate, as described below. The prepreg is cut into a desired shape and laminated with copper foil or the like as needed. The laminate is then heated and cured while applying pressure to the laminate by press molding, autoclave molding, sheet winding molding, or the like, to obtain an electrical and electronic laminate (printed wiring board) or a carbon fiber reinforced material.

[0069] The cured product of this embodiment can be used in various applications such as molding materials, adhesives, composite materials, paints, etc. The cured product of the curable resin composition described in this embodiment exhibits excellent heat resistance and dielectric properties, and is therefore suitable for use in electric and electronic parts such as encapsulants for semiconductor elements, encapsulants for liquid crystal display elements, encapsulants for organic EL elements, printed wiring boards, and build-up laminates, as well as composite materials for lightweight, high-strength structural materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

[0070] (Another embodiment) The cured product of this embodiment can also be used as a resist film, an interlayer insulating material for a build-up method, or an optical waveguide in a printed circuit board, or as an electrical, electronic, or optical substrate such as an optoelectronic substrate or optical substrate. Specific examples of these include computers, home appliances, and mobile devices. The film thickness of this cured product layer is typically about 0.5 to 160 μm, and preferably about 1 to 100 μm.

[0071] The curable resin composition of this embodiment preferably contains a photopolymerization initiator. The photopolymerization initiator is preferably a photoradical polymerization initiator or a photocationic polymerization initiator. The content of the photopolymerization initiator is 0.001 to 20 parts by mass, more preferably 0.002 to 15 parts by mass, per 100 parts by mass of the resin component. If the content is less than 0.001 part by mass, photocuring may be insufficient, and if the content is more than 20 parts by mass, dielectric properties may deteriorate. Preferred examples of photopolymerization initiators are listed below, but the present invention is not limited to these. These may be used alone or in combination of two or more types.

[0072] Photoradical polymerization initiator: The photoradical polymerization initiator is not particularly limited as long as it is a compound that generates radicals and initiates a chain polymerization reaction when irradiated with ultraviolet light or visible light. Examples of the photoradical polymerization initiator include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, and diphenyl disulfide. Specific examples include IRGACURE (registered trademark) 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, OXE-01, OXE-02, OXE-03, OXE-04, DAROCUR (registered trademark) 1173, LUCIRIN (trademark) TPO (all manufactured by BASF Japan Ltd.), SEIQOL (registered trademark) Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Chemical Co., Ltd.), and KAYACURE (registered trademark) DETX-S (manufactured by Nippon Kayaku Co., Ltd.). Among these, preferred are the oxime ester initiators IRGACURE OXE01, OXE02, OXE03, and OXE04.

[0073] Photocationic polymerization initiator: The photocationic polymerization initiator is not particularly limited as long as it is a compound that generates a cationic species such as a Bronsted acid or a Lewis acid upon irradiation with ultraviolet light or visible light, and examples thereof include aromatic iodonium complex salts and aromatic sulfonium complex salts. Specific examples of aromatic iodonium complex salts include diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di(4-nonylphenyl)iodonium hexafluorophosphate, tolylcumyliodonium tetrakis(pentafluorophenyl)borate (manufactured by Rhodia, trade name: Rhodosil PI2074), and di(4-tert-butyl)iodonium tris(trifluoromethanesulfonyl)methanide (manufactured by BASF, trade name: CGIBBI-C1). Specific examples of aromatic sulfonium complex salts include 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by San-Apro Co., Ltd., trade name: CPI-101A), thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate (manufactured by San-Apro Co., Ltd., trade name: CPI-210S), 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate (manufactured by ADEKA Corporation, trade name: SP-172), and a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate (manufactured by ACETO Corporation, trade name: SP-172). Examples of such sulfonyl esters include triphenylsulfonium tris(trifluoromethanesulfonyl)methanide (manufactured by BASF, trade name: CGITPS-C1), tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tris(trifluoromethylsulfonyl)methide (manufactured by BASF, trade name: GSID26-1), and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate (manufactured by BASF, trade name: Irgacure PAG290).Among these, aromatic sulfonium complex salts are preferred in the present invention because they have high vertical rectangular processability and high thermal stability in the photosensitive image formation process. Among these, 4-{4-(2-chlorobenzoyl)phenylthio}phenylbis(4-fluorophenyl)sulfonium hexafluoroantimonate, a mixture of aromatic sulfonium hexafluoroantimonates containing 4-thiophenyldiphenylsulfonium hexafluoroantimonate, and tris[4-(4-acetylphenyl)sulfonylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)borate are particularly preferred.

[0074] The curable resin composition of this embodiment can be used by known methods. For example, the curable resin composition of the present invention, the viscosity of which has been adjusted with an organic solvent, can be applied to a support, and then dried at 50 to 180°C, preferably 80 to 140°C, for 5 to 30 minutes to form a film-like curable resin composition. Examples of the support include silicon wafers, ceramic substrates, rigid substrates, flexible substrates, and silicon wafers on which an inorganic surface protection film such as a SiN film or a SiO2 film has been formed.

[0075] The coating method is not particularly limited, and examples include coating using a spin coater, slit coater, roll coater, etc., and screen printing. Among these, for example, as a coating method for silicon wafers, it is preferable to adopt a coating method using a spin coater. Furthermore, the film thickness of the film-like curable resin composition can be adjusted as desired by adjusting the concentration of the curable resin composition and the coating thickness, and is not particularly limited. For example, when used as a protective film for semiconductor elements or an interlayer insulating film, the film thickness after drying is preferably 3 to 50 μm, more preferably 5 to 30 μm, and even more preferably 5 to 20 μm. If the film thickness is less than 3 μm, the elements and circuits underneath the film tend not to be sufficiently protected, and if it exceeds 50 μm, it tends to be difficult to form fine patterns. In the present invention, even if the film thickness is 10 μm or more (preferably 10 to 20 μm), it is possible to form a fine pattern, and it is possible to form a pattern in which the aspect ratio of the opening diameter (Via diameter) of the through-hole formed by exposure and development described below is 0.3 or more (more preferably 0.5 or more).

[0076] Next, the film-like curable resin composition thus obtained is exposed to light through a mask having a predetermined pattern, thereby photopolymerizing the curable resin composition of the present invention. Examples of the exposure method include contact exposure and reduced projection exposure. The exposure wavelength is preferably ultraviolet to visible light of 200 to 500 nm, and a standard reduced projection exposure machine (stepper) can be used. Furthermore, from the viewpoint of being able to form a fine pattern, the exposure wavelength is more preferably 256 to 436 nm, and even more preferably 256 to 365 nm. The exposure dose is not particularly limited, but is preferably 100 to 5,000 mJ / cm. ２ is preferably 300 to 3000 mJ / cm ２ It is more preferable that:

[0077] Next, development is performed to dissolve and remove the unexposed portions of the film-shaped curable resin composition after exposure, thereby obtaining a polymerized film (polymer) having a predetermined pattern. That is, in the exposed portions, radicals or cationic species generated from the photopolymerization initiator upon light irradiation cause crosslinking of component (A) and other compounds, thereby rendering them insoluble in the developer. In contrast, the unexposed portions dissolve in the developer, and by utilizing the difference in solubility between the exposed and unexposed portions in the developer, a polymerized film having a pattern such as through-holes with a predetermined opening diameter (Via diameter) can be obtained. In addition to using the above-mentioned solvents, the developer may further contain an alcoholic solvent such as methanol, ethanol, or propanol to adjust solubility during development. Examples of the development method include spraying, puddling, and dipping.

[0078] It is also preferable to further rinse the polymer film having the predetermined pattern obtained by the development with an organic solvent such as cyclopentanone or a mixed solvent of cyclopentanone and ethanol. From the viewpoints of suppressing the occurrence of surface roughness and facilitating dimensional design, it is preferable that the polymer film after the development has a residual film ratio of 90% or more. In the present invention, the residual film ratio refers to the ratio of the film thickness of the polymer film after development to the film thickness of the film-like curable resin composition after drying (before exposure) (film thickness of the polymer film after development / film thickness of the film-like curable resin composition after drying (before exposure)).

[0079] Next, the polymer film having the predetermined pattern obtained by the development is heated and cured as necessary to obtain a cured film (cured product) having the predetermined pattern. The heating temperature (curing temperature) is preferably 60 to 230°C, and more preferably 150 to 230°C. The heating time is preferably 30 to 120 minutes. In the present invention, the curing temperature refers to the temperature required to thermally cure functional groups remaining unreacted at the time of exposure by a thermal reaction.

[0080] Thus, by using the curable resin composition of the present invention, a cured film having a fine pattern can be obtained. The aspect ratio of the opening diameter (via diameter) of the formed through-holes in the pattern is preferably 0.3 or more, more preferably 0.5 or more. In the present invention, the opening diameter can be determined by measurement using an optical microscope or a scanning electron microscope (SEM).

[0081] The cured product obtained by photocuring or photothermal curing (curing using a combination of photocuring and thermal curing) using the curable resin composition of the present invention can be suitably used for at least one film selected from the group consisting of a surface protective film for a semiconductor element, an interlayer insulating film, and an insulating film for a redistribution layer. Furthermore, the curable resin composition of the present invention is particularly effective when such a film requires a film thickness of 10 μm or more and patterning is required so that the aspect ratio of the opening diameter (via diameter) of the through hole is 0.3 or more (more preferably 0.5 or more).

[0082] The present invention will now be described in more detail with reference to examples. Unless otherwise specified, all parts are by weight. However, the present invention is not limited to these examples.

[0083] The various analytical methods used in the examples are described below. <Gel permeation chromatography (GPC)> Apparatus: ACQUITY APC system (manufactured by Waters) Column: Guard column SHODEX GPC KF-601 (2 columns), KF-602 KF-602.5, KF-603 Flow rate: 1.23 ml / min Column temperature: 25°C Solvent used: THF (tetrahydrofuran) Detector: RI (differential refractometer)

[0084] Synthesis Example 1 A flask equipped with a thermometer, a condenser, and a stirrer was charged with 30.1 parts of toluene, 10.0 parts of n-methylpyrrolidone, 6.35 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), and 0.25 parts of methanesulfonic acid. After confirming that the solution was homogeneous, 19.8 parts of styrene-maleic anhydride copolymer (acid value: 85, Mn: 1,979, Mw: 3,088) was charged into a dropping funnel, and the styrene-maleic anhydride copolymer was added to the flask over 5 hours at 120 ° C., followed by a reaction for 10 hours at 120 ° C. After allowing to cool, 15.0 parts of toluene, 5.0 parts of n-methylpyrrolidone, and 3.56 parts of maleic anhydride were added to the flask, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 285 parts of toluene, and the organic layer was washed six times with 100 parts of 10 wt % saline and three times with 100 parts of warm water. The solvent was distilled off under heating and reduced pressure to obtain the desired maleimide resin mixture (M-1) as a brown solid resin. The GPC chart of the resulting compound is shown in Figure 1. The proportion of component (c) calculated from the peak area ratio was 17.7% in terms of GPC area percentage. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 26.7 and n was calculated to be 2.3.

[0085] [Synthesis Example 2] A flask equipped with a thermometer, a condenser, and a stirrer was charged with 26.9 parts of toluene, 8.95 parts of n-methylpyrrolidone, 17.30 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), and 0.69 parts of methanesulfonic acid. After confirming that the solution was homogeneous, 36.4 parts of styrene-maleic anhydride copolymer (acid value: 150, Mn: 2,454, Mw: 4,997) was added and the mixture was reacted at 115 ± 2 ° C. for 15 hours. After cooling, 13.4 parts of toluene, 9.0 parts of n-methylpyrrolidone, and 14.4 parts of maleic anhydride were added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 645 parts of toluene, and the organic layer was washed four times with 245 parts of 10 wt % saline and three times with 245 parts of warm water. The solvent was distilled off under heating and reduced pressure to obtain the target maleimide resin mixture (M-2) as a toluene solution. The GPC chart of the obtained compound is shown in Figure 2. The proportion of component (c) calculated from the peak area ratio was 17.2% in terms of GPC area percentage. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 41.5 and n was calculated to be 6.7.

[0086] Comparative Synthesis Example 1: A flask equipped with a thermometer, a condenser, and a stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 8.47 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.17 parts of methanesulfonic acid, and 18.7 parts of a styrene-maleic anhydride copolymer (acid value: 60, Mn: 6,686, Mw: 11,295), and the mixture was allowed to react at 120°C for 2 hours. After cooling, 5.88 parts of maleic anhydride was added, and the reaction was continued under reflux for 6 hours. After cooling, the reaction solution was diluted with 50 parts of toluene, and the organic layer was washed five times with 100 parts of warm water. The solvent was distilled off under heating and reduced pressure, yielding the desired maleimide resin mixture (M-3) as a brown solid resin. The GPC chart of the resulting compound is shown in Figure 3. The proportion of component (c) calculated from the peak area ratio was 37.7% in terms of GPC area percentage. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 92.4 and n was calculated to be 5.4.

[0087] Comparative Synthesis Example 2: A flask equipped with a thermometer, a condenser, and a stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 14.12 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.28 parts of methanesulfonic acid, and 23.4 parts of a styrene-maleic anhydride copolymer (acid value: 120, Mn: 5,984, Mw: 14,768), and the mixture was allowed to react at 120°C for 3 hours. After cooling, 9.81 parts of maleic anhydride was added, and the reaction was continued under reflux for 8 hours. After cooling, the reaction solution was diluted with 100 parts of toluene, and the organic layer was washed five times with 100 parts of warm water. The solvent was distilled off under heating and reduced pressure to obtain the target compound (M-4) as a brown solid resin (Mn: 1210, Mw: 8644). The GPC chart of the resulting compound is shown in Figure 4. The proportion of component (c) calculated from the peak area ratio was 37.8%. From the acid value and molecular weight of the raw material styrene-maleic anhydride copolymer, m was calculated to be 116.2 and n was calculated to be 14.4.

[0088] Comparative Synthesis Example 3 A flask equipped with a thermometer, a condenser, and a stirrer was charged with 75.0 parts of toluene, 25.0 parts of n-methylpyrrolidone, 5.65 parts of 4,4'-methylenebis(2-ethyl-6-methylaniline), 0.11 parts of methanesulfonic acid, and 18.7 parts of a styrene-maleic anhydride copolymer (acid value: 60, Mn: 6,686, Mw: 11,295), and the mixture was allowed to react at 120°C for 2 hours. After cooling, 2.94 parts of maleic anhydride was added, and the reaction was continued under reflux for 17 hours. After cooling, the reaction solution was diluted with 50 parts of toluene, and an attempt was made to wash the organic layer with 100 parts of warm water, but the organic layer and the aqueous layer did not separate.

[0089] <Solvent Solubility and Storage Stability Tests> The maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2, and the maleimide resin (Mn: 2126, Mw: 11527) described in Example 12 of Japanese Patent No. 7208705 were diluted with toluene to a resin content of 60% by weight. As a result, the maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2 were dissolved in toluene, but the maleimide resin described in Example 12 of Japanese Patent No. 7208705 was not dissolved in toluene. Next, 1 g of each of the solutions of the maleimide resin mixtures M-1, M-3, and M-4 obtained in Synthesis Example 1 and Comparative Synthesis Examples 1 and 2, which had been diluted with toluene to a resin content of 60% by weight, was placed in a 6 cc screw cap vial, sealed with a lid, and allowed to stand in a refrigerator at 5.0 to 10.0°C for 24 hours, after which the presence or absence of crystal precipitation was visually confirmed. Those exhibiting no crystal precipitation were evaluated as ◯ (good storage stability), and those exhibiting precipitation were evaluated as × (poor storage stability). The results are shown in Table 1. Since the maleimide resin described in Example 12 of Japanese Patent No. 7208705 did not dissolve in toluene under the above conditions, the amount of toluene was increased to confirm its solubility. It was confirmed that the maleimide resin did not dissolve in toluene at a resin content of 60 to 20 wt%, but dissolved in toluene at a resin content of 10 wt%. Thus, 1 g of a solution of the maleimide resin described in Example 12 of Japanese Patent No. 7208705, diluted with toluene to a resin content of 10 wt%, was placed in a 6 cc screw cap bottle, sealed with a lid, and allowed to stand at room temperature for 24 hours. The presence or absence of crystal precipitation was then visually confirmed. The presence of precipitation was confirmed.

[0090]

[0091] From the results in Table 1, it was confirmed that the maleimide resin mixture obtained in Synthesis Example 1 had excellent solvent solubility and storage stability in the solution state (varnish).

[0092] [Examples 1 to 7] A 250 μm thick cushion paper with a 150 mm x 150 mm cutout in the center was placed on a first copper foil. 5.0 g of a sample of the curable resin composition formulated according to the ratios shown in Table 2 was placed in the center of the frame, and a second copper foil was placed on top of the cushion paper and sample. The cushion paper and sample sandwiched between the first and second copper foils were heated and pressurized in a vacuum heating press to form a sample, which was then cured at 220°C for 2 hours. The first and second copper foils were then etched using ferric chloride to obtain a cured film. The dielectric loss tangent and glass transition temperature (Tg) of the cured film were measured using the methods described below and are shown in Table 2.

[0093] <Dielectric tangent test> Tests were conducted at 25°C using a 10 GHz cavity resonator manufactured by AET Corporation using the cavity resonator perturbation method. The test was conducted on a sample with a width of 2.5 mm, length of 50 mm, and thickness of 0.25 mm. <Dynamic viscoelasticity measurement (DMA)> Dynamic viscoelasticity measuring device: DMA Q800 (TA instruments) Measurement temperature range: 30 to 350°C Heating rate: 2°C / min Frequency: 10 Hz Sample size: Width 5 mm x length 40 mm x thickness 0.25 mm Criterion: The temperature at which the loss factor (tan δ) = (loss modulus G") / (storage modulus G') is maximized is taken as the glass transition temperature (Tg).

[0094]

[0095] M-5 (maleimide resin obtained by the method described in Synthesis Example 2 of WO 2022 / 210433, from which the solvent was distilled off by heating under reduced pressure) NC-3000 (epoxy resin, manufactured by Nippon Kayaku Co., Ltd.) Unifiner W-575 (activated ester, manufactured by Unitika Ltd.) SA-9000-111 (polyphenylene ether compound having a methacrylate structure, manufactured by Sabic) OPE-2St 1200 (polyphenylene ether compound having a styrene structure, manufactured by Mitsubishi Gas Chemical Company, Inc.) OPE-2St 2200 (polyphenylene ether compound having a styrene structure, manufactured by Mitsubishi Gas Chemical Company, Inc.) Acenaphthylene (manufactured by JFE Chemical Corporation) Phenylmaleimide (manufactured by Tokyo Chemical Industry Co., Ltd.) BisA-OCN (2,2-bis(4-cyanatophenyl)propane, manufactured by Mitsubishi Gas Chemical Company, Inc.) DCP (Dicumyl peroxide, manufactured by Kayaku Nouryon Co., Ltd.) 18% Octope Zn (manufactured by Hope Pharmaceutical Co., Ltd.)

[0096] From the results in Table 2, it was confirmed that Examples 1 to 7 had excellent low dielectric dissipation factor. The attenuation rate of a signal flowing through the dielectric material constituting a printed wiring board is proportional to the dielectric dissipation factor. Since signal attenuation directly generates heat and causes a rise in temperature, a low dielectric dissipation factor is important for printed wiring board materials and the like.

[0097] Example 8 A photosensitive resin composition formulated in the proportions shown in Table 3 was applied to a rolled copper foil BHY-82F-HA-V2 (manufactured by JX Nippon Mining & Metals Corporation) using an applicator to a thickness of 20 μm. The coating film was dried in a hot air dryer at 80° C. for 30 minutes, and then irradiated with an ultraviolet ray from a UV irradiator (manufactured by GS YUASA: CS 30L-1) at 500 mJ / cm . ２ The copper foil was then etched using ferric chloride to obtain a cured film. The dielectric loss tangent of the cured film was measured using the method described below, and the results are shown in Table 3. [Example 9] A photosensitive resin composition formulated in the proportions shown in Table 3 was applied to rolled copper foil BHY-82F-HA-V2 (manufactured by JX Nippon Mining & Metals Corporation) with an applicator to a thickness of 20 μm. The coating film was then dried in a hot air dryer at 80°C for 30 minutes, and then exposed to an ultraviolet irradiator (GS YUASA: CS 30L-1) at 500 mJ / cm. ２The coating was cured by irradiating ultraviolet light of 1000 kJ / cm 2 at 220°C for 60 minutes. After heating and curing in an oven at 220°C for 60 minutes, the copper foil was etched with ferric chloride to obtain a cured film. The dielectric loss tangent of the cured film was measured using the method described below, and the results are shown in Table 3.

[0098] <Dielectric Loss Tangent Test> A test was performed by a cavity resonator perturbation method at 25° C. using a 10 GHz cavity resonator manufactured by AET Co., Ltd. The test was performed on a sample with a width of 1.7 mm, a length of 100 mm, and a thickness of 1.7 mm.

[0099]

[0100] OXE-04 (manufactured by BASF Japan Ltd.)

[0101] Conventional solder resists have a dielectric loss tangent of approximately 0.017 to 0.032 (see Table 1 in "Latest Technological Trends in Insulating Materials for Printed Wiring Boards" (Journal of the Japan Society of Electronics Packaging, Vol. 21, No. 3, 2018, pp. 202-206). The results in Table 3 show that Examples 8 and 9 have a lower dielectric loss tangent than conventional solder resists.

[0102] The curable resin composition of the present invention and its cured product are useful for applications such as insulating materials for electric and electronic components (such as highly reliable semiconductor encapsulating materials), laminates (such as printed wiring boards, BGA substrates, and build-up substrates), resist films, printed circuit boards as optical waveguides, substrates for electric, electronic, and optical substrates such as optoelectronic substrates and optical substrates, adhesives (such as conductive adhesives), and various composite materials including CFRP, paints, and 3D printing.

Claims

1. A curable resin composition containing a maleimide resin having repeating units of the following formulas (a) and (b) and a maleimide resin mixture composed of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the following formula (c), wherein the content of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane represented by the formula (c) in the total amount of the maleimide resin mixture is 5.0 to 30.0 area% in terms of GPC area percentage. In the above formula (a), m is the average value of the number of repetitions, and 0 < m < 200. In the above formula (2), n is the average value of the number of repetitions, and 0 < n < 100. (a) and (b) are each bonded by *, and the repeating positions may be random.

2. The curable resin composition according to claim 1, wherein the maleimide resin mixture is obtained by reacting a styrene-maleic anhydride copolymer, 4,4'-methylenebis(2-ethyl-6-methylaniline), and maleic anhydride.

3. The curable resin composition according to claim 2, wherein the weight average molecular weight of the styrene-maleic anhydride copolymer is 900 or more and less than 10,000.

4. The curable resin composition according to claim 1, further containing at least one selected from the group consisting of maleimide resins other than the maleimide resin mixture, polyphenylene ether compounds, compounds having an ethylenically unsaturated bond, cyanate ester resins, polybutadiene and its modified products, polystyrene and its modified products, polyethylene and its modified products.

5. The curable resin composition according to claim 1, further containing a curing accelerator.

6. The curable resin composition according to claim 1, further containing a photo radical polymerization initiator.

7. The curable resin composition according to claim 6, which is for a resist.

8. The curable resin composition according to claim 1, which is for a printed wiring board.

9. A varnish comprising the curable resin composition according to any one of claims 1 to 8 and an organic solvent.

10. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 8.

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